Biosaintifika

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Journal of Biology & Biology Education http://journal.unnes.ac.id/nju/index.php/biosaintifika

Seedling Production of Pak Choy (Brassica rapa L.) using Organic and Inorganic Nutrients

Dody Priadi, Fiqolbi Nuro

DOI: 10.15294/biosaintifika.v9i2.8537

Research Center for Biotechnology, Indonesian Institute of Sciences, Indonesia

Abstract

Pak Choy or Bok Choy (Brassica rapa L. var. chinensis) is one of favorite Chinese leafy vegetable for various dishes in Indonesia. In this study, it was used as a plant model to identify the appropriate organic hydroponic nutrient solution for leafy vegetable seedling production. The seed was sown on rock wool slabs submerged with 200 ml of a nutrient solution containing biofertilizer of Beyonic StarTmik@Lob (0, 25, 50, 75, and 100%). commercial hydroponic solution (0, 25, 50, 75, and 100%) and its combination (25, 50, and 75%). The experiments were arranged in a CRD.

Meanwhile, the obtained data was analyzed using ANOVA followed by DMRT.

The relationship among growth parameters was observed using Pearson correlation analysis. The result of the study showed that the combination of organic and inorganic nutrient (25% Beyonic StarTmik@Lob and 75% commercial hydroponic solution) resulted in the highest seedling growth parameters and leaf indices as well as the perfectly positive correlations among growth parameters. This result indicated that the use of organic nutrient alone was not appropriate for hydroponic seedling production of Pak Choy. Therefore, further study needs to be done to identify the hydroponic solution without inorganic nutrients towards the organic vegetable production.

How to Cite

Priadi, D., & Nuro, F. (2017). Seedling Production of Pak Choy (Brassica rapa L.) using Organic and Inorganic Nutrients. Biosaintifika: Journal of Biology & Biology Education, 9(2), 217-224.

Received 23 January 2017 Approved 11 May 2017 Published 17 August 2017

Keywords

Brassica rapa L. var. chinensis;

hydroponic; organic nutrients;

Pak Choy; seedling production

 Correspondence Author:

Jl. Raya Bogor Km.46 Cibinong 16911 E-mail: [email protected]

p-ISSN 2085-191X e-ISSN 2338-7610

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nic culture technique to identify the appropriate organic nutrient solution for Pak Choy seedling production prior a transplanting to the soil or soilless medium.

METHODS

This study was conducted from October to December 2016 in the screen house of the Germplasm Garden of RC for Biotechnology- LIPI, Cibinong, West Java. The average tempe- rature in the screen house was 33.4°C with the relative humidity (RH) of 60.7%.

The commercial seed of Pak Choy (Brassi- ca rapa Var. Nauli), produced by East-West Seed Company were obtained from a local farm shop in Bogor; West Java was used in this study. The organic nutrient solution was obtained from bio- organic fertilizer of Beyonic StarTmik@Lob (25 ml/l water) produced by Research Center for Biology-LIPI, whereas a commercial hydroponic solution (Raja Hidroponik) (5 ml/l) was used for the inorganic nutrient source. The seeds were sown manually on each 1 cm³ rock wool slabs submerged in a 200 ml of nutrient solution in a plastic container (25 x 20 x 3 cm). Groundwater moistened the rock wool slabs before seed sowing. Each container consists of 25 rock wool slabs containing inorganic and organic nutrient (Table 1).

The degree of acidity (pH) and electrical conductivity (EC) of the nutrient solution were done using water/soil (2:1) extraction method at the beginning and the end of germination period using a digital portable pH and EC meter (Adwa AD1000). Seedling height was measured using a digital caliper (Nankai). Seedling leaf area was calculated using digital image analysis method (Bradshaw et al., 2007). This approach has been used by researchers in a variety of application (Priadi et al., 2016) due to the simple, inexpensive and accurate method. The water content of Pak Coy seedling was measured on a fresh weight ba- sis method according to ISTA (2006) using a drying oven (Zenith Lab DHG9053A) at 130°C for 2 hours.

Germination parameter of the Pak Choy seedlings was germinability and germination rate.

Seedling growth was observed daily and taken from 25 seedlings for each replication. Seedling height and diameter, whole leaves and roots, and leaf area were observed at the end of germination period (day-14)taken from five seedlings of each replication. Seedling emergences were recorded per day when a normal seedling was visible above the rock wool slabs. The leaf indices of SLA INTRODUCTION

Pak Choy or Bok Choy (Brassica rapa) was introduced to South-East Asia in the 15^th centu- ry. Nowadays it is widely cultivated in this re- gion including Indonesia. Pak Choy is one of favorite Chinese leafy vegetable in Indonesia.

All above ground part of this vegetable is edible mainly its succulent petiole. It is not commonly eaten raw but used in main ingredients for soup and stir-fried dishes. Each of 100 g edible part of Pak Choy contains protein 1.7 g, fat 0.2 g, Carbohydrate 3.1 g, vitamins and minerals such as β-carotene (2.3 mg), vitamin C (53 mg) and Calcium (102 mg) (Tay & Toxopeus, 1994). The national production of Brassica in 2015 is 600,200 tons (Central Agency on Statistics of Indonesia, 2015). This vegetable is commonly produced by conventional farming using inorganic fertilizer to enhance crop productivity. Nowadays, the de- mand of organic vegetable is increased due to the public concern about healthy food, free from chemical residues. Organic farming of cauliflower (B. oleacera var. botrytis) in lowland area showed a better vegetative growth but not for generative growth (Widiatningrum & Pukan, 2010). Or- ganic farming of another Brassica species (cauliflower) was successfully done. Therefore, the organic vegetable seedling production plays an important role, because it is the initial step in the practice of biological farming. Moreover, Kubo- ta et al. (2013) stated that the use of high-quality planting materials is critical for success in greenhouse plant production.

The viability of small seed including Pak Coy is usually tested using a paper substrate (Purbojati & Suwarno, 2006). However, seedling production is commonly using a locally organic substrate such as peat and vermicompost (Tuzel et al., 2014), spent mushroom compost (Priadi et al., 2016) on tomato seedling, and coconut coir dust on lettuce (Lactuca sativa L.) (Hossain et al., 2016). Moreover, production of organic tran- splants involves more than organic fertilizer and substrates and avoiding the use of non-approved pesticides. These organic substrates are also as an organic nutrient source with or without the addition of inorganic and organic fertilizer. A study on the feasibility of organic nutrient solution for the hydroponic culture of leafy green vegetable was conducted by Ferguson et al. (2014).

Also, the seedling production of peppermint and spearmint using inorganic and organic fertilization was previously performed by Akoumianaki- Ioannidou et al. (2010). In this study, we use both inorganic and organic nutrients using a hydropo-

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(Specific Leaf Area) and LAR (Leaf Area Ratio) were recorded to evaluate the seedling resistance at transplant (Herrera et al., 2008). The SLA is the ratio of leaf area to leaf dry weight. Meanw- hile, LAR is the ratio of leaf area to dry seedling weight.

The experiments were arranged in a Completely Randomized Design (CRD) with 3 replications. Obtained data was analyzed using Analysis of Variance (ANOVA) followed by Duncan’s Multiple Range Test (DMRT). The relationship among growth parameters was observed using Pearson correlation analysis. Data was processed using statistical software SPSS 16.0.

RESULTS AND DISCUSSION

Data in Table 2 showed that pH and EC value of the nutrient solution at the end of germination period were higher than that the initial.

The higher pH is caused by anion uptake by the plant during plant growth period. Meanwhile, the higher EC is due to the high level of nutrient due to the additional nutrient solution for adjustment (Hossain et al., 2016).

Seedling Emergence

Seedling emergence is one of the important parameter as well as emergence rate. The highest all seedling growth parameter was obtained by the Pak Choy seed sown on the rock wool slabs containing 100% of groundwater (K0- 1). It was not significantly different with K0-1 when the seed was sown on the rock wool slabs containing the mixture of organic and inorganic solution (25% Beyonic StarTmik@Lob and 75%

commercial hydroponic solution). Contrary, the mixture of 75% Beyonic StarTmik@Lob and 25%

commercial hydroponic solution (K3) resulted in

the lowest seedling growth. A biofilm was formed on the root surface of the seedling in the hydroponic solution containing 100% Beyonic StarT- mik@Lob (K0-3). Seedling growth of Pak Choy on K-03 was lower due to the biofilm formation.

A study conducted by Chinta et al. (2015) found that a biofilm was formed on the root surface of organic hydroponic lettuce; in contrast, chemical hydroponics resulted in a lack of biofilm. Biofilm is formed as an interaction between beneficial microorganism and lettuce roots. Another study conducted by Fujiwara et al. (2012) on tomato seedlings found that a rhizosphere biofilm in the organic hydroponic may be responsible for the suppression of the bacterial wilt. In this study, we found that the use of Beyonic StarTmik@Lob alone as a nutrient solution for Pak Choy hydroponic seedling production seemed to be not appropriate to obtain optimal growth (Table 3).

Leaf Indices

The highest leaf number (5.067) was obtained from the hydroponic solution containing 100% commercial hydroponic solution (K0-2). It was not significantly different with those containing both K4 and K5. The mixture of inorganic and organic nutrient solution of K4 and K5 resulted in the best leaf area. The best SLA index was obtained from K4 nutrient solution. Accor- ding to Herrera et al. (2008), the lower SLA value indicated, the higher transplant stress resistance.

The LAR represents the relationship between photosynthetic material and respiratory material in the plant. It is also used for evaluation of seedling resistance at transplant. Higher LAR indica- tes more biomass production for seedling growth.

Table 4 showed that there was not significantly different in both of SLA and LAR among the nutrient solution used except the K0-3.

Table 1. Composition of nutrient solution for hydroponic seedling production of Pak Choy Code Composition

K0-1 100% groundwater

K0-2 100% commercial hydroponic solution

K0-3 Beyonic StarTmik@Lob at the producer’s recommended concentration*

K1 25% K0-3+75% groundwater K2 50% K0-3+50% groundwater K3 75% K0-3+25% groundwater K4 25% K0-3+75% K02

K5 50% K0-3+50% K02 K6 75% K0-3+25% K02 Note*=25 ml in 1 liter of water

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Seedling dry weight

The highest Pak Choy seedling dry weight was obtained in the hydroponic solution containing biofertilizer of Beyonic StarTmik@Lob (K- 03) (Table 5 and Figure 1). This biofertilizer was supported by PGPR (Plant growth promoting rhizobacteria) (Dewi et al., 2015). It was suggested that the higher seedling dry weight was affected by the hydroponic solution containing PGPR as explained by Bashan & de-Bashan (2010), since PGPR at the very early stage leading to better ab- sorption of water and minerals. The result of this study agrees with a study conducted by Das et al.

(2014) on organically cultivated mungbean using the organic manure containing PGPR.

The lower seedling dry weight was obtained on a mixture of organic and inorganic nutrient solution (25% Beyonic StarTmik@Lob and 75% inorganic nutrient solution). The dry seedling weight of Pak Choy seems to be affected by the availability of Beyonic StarTmik in the nut-

rient solution. A study conducted by Ferguson et al. (2014) showed that hydroponic culture of Bok Choy using organic nutrient solution resulted in the lower yield compared with those low or high- level inorganic nutrients. Nevertheless, the price of the organic product is much higher than the conventional product.

Correlation among growth parameters

Correlation among Pak Choy seedling growth parameters in the nutrient solution used is varied. There was perfectly positive correlation between total leaves (TL) and both stem dry weight (SW) and whole seedling dry weight (TW) as well as the correlation between leaf area (LA) and TW and between SW and TW on K4 nutrient solution (Table 6). It was reasonable that the increased in the whole seedling dry weight was affected by the increased of total leaves, leaf area and stem dry weight. Table 6 showed that the correlation among those seedling growth pa- Table 2. Characteristic of nutrient solution of Pak Choy hydroponic culture

Nutrient Solution Initial Final

pH EC (dS m^-1) pH EC (dS m^-1)

K0-1 5.91 0.0 7.25 0.3

K0-2 4.53 2.2 6.44 9.7

K0-3 3.98 0.7 6.79 4.7

K-1 4.09 0.5 6.88 1.0

K-2 4.12 0.3 6.91 1.5

K-3 4.62 0.1 6.86 2.4

K-4 5.06 1.5 7.20 3.1

K-5 4.86 1.2 7.43 4.1

K-6 4.15 1.5 7.48 4.3

Table 3. Growth parameter of Pak Choy seedlings after 14-days sowing on rock wool slabs containing inorganic and organic nutrient solution in the screen house

Nutrient Solution

Emergence (%)

Rate of emergence

Height (cm)

Diameter (cm)

Total roots K0-1 98.667 a 7.047 a 1.580 bcd 0.9933 abc 11.800 a K0-2 85.333 ab 6.093 ab 1.800 bc 1.0733 a 12.267 a K0-3 60.000 bcd 4.288 bcd 2.033 b 0.7500 d 6.933 d K-1 77.333 abc 5.524 abc 1.587 bcd 0.9267 abc 10.467 b K-2 49.333 cd 3.520 cd 1.373 cd 0.9067 bc 10.400 b

K-3 36.000 d 2.570 d 1.200 d 0.8633 cd 8.733 c

K-4 78.667 abc 5.620 abc 2.847 a 1.0633 ab 12.400 a K-5 66.667 bcd 4.763 bcd 2.573 a 1.0667 ab 12.067 a K-6 56.000 bcd 3.997 bcd 1.873 b 0.9600 abc 10.333 b

Note: Means in the same column followed by the different letter are significantly different (p<0.05) according to DMRT

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rameters seemed to be affected by the biofertilizer and inorganic nutrient proportion in the hydroponic solution of K-4 (25% K0-3+75% K02). In contrast, there was not any significant differen- ce correlation among growth parameters in K-6 (75% K0-3+25% K02). A different result showed

by tomato seedling grown on various compost types; there was a very significant correlation between leaf area and both dry leaf weight and whole seedling dry weight, as well as seedling height and diameter (Priadi et al., 2016). The correlation among seedling growth parameters seemed to Table 4. Leaf indices of Pak Choy seedlings after 14-days sowing on rock wool slabs containing inorganic and organic nutrient solution in the screen house

Nutrient Solution

Leaf number

Leaf area (mm²)

SLA (mm²/ mg)

LAR (mm²/mg) K0-1 4.067 c 88.000 c 84.137 a 53.887 a K0-2 5.067 a 162.365 b 84.767 a 57.170 a

K0-3 2.933 d 52.540 e 9.250 b 5.187 b

K-1 4.000 c 71.111 d 112.763 a 68.903 a K-2 3.800 c 62.753 de 132.373 a 67.907 a K-3 3.667 c 53.663 e 132.440 a 65.480 a K-4 5.000 a 231.022 a 95.697 a 61.287 a K-5 5.000 a 238.703 a 107.717 a 75.223 a K-6 4.533 b 154.699 b 119.843 a 75.380 a

Table 5. Dry weight of Pak Choy seedlings after 14-days sowing on rock wool slabs containing inorganic and organic nutrient solution in the screen house

Nutrient Solution

Stem (mg)

Leaves (mg)

Roots (mg)

Whole (mg)

K0-1 0.157 cd 1.047 de 0.437 b 1.637 cd

K0-2 0.523 cd 2.017 bcd 0.457 b 2.993 bc

K0-3 1.900 a 5.687 a 2.640 a 10.227 a

K-1 0.090 d 0.633 e 0.313 b 1.033 d

K-2 0.137 cd 0.483 e 0.317 b 0.937 d

K-3 0.140 cd 0.380 e 0.250 b 0.767 d

K-4 1.017 b 2.993 b 0.550 b 4.560 b

K-5 0.607 bc 2.277 bc 0.380 b 3.267 bc

K-6 0.467 cd 1.433 cde 0.327 b 2.227 cd

A B C D E F G H I

Figure 1. Seedling performance of Pak Choy after 14-day sowing in various hydroponic nutrient solution (A= K0-1, B= K0-2, C= K0-3, D=K1, E=K2, F=K3, G=K4, H=K5, I=K6)

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Tabel 6. Correlation of growth parameters of Pak Choy seedling in various nutrient solution Parameter

K01

Nutrient Solution

K02 K03 K1 K2 K3 K4 K5 K6

HT

DM -1.000* -0.993 -.905 -0.954 -0.422 0.723 0.347 0.854 0.589

TL 0.596 -0.596 0.270 n/a 0.973 0.827 0.667 n/a -0.858

LA 0.885 0.924 0.919 -0.034 0.614 -0.127 0.951 0.123 -0.536 TR 0.986 0.993 0.969 0.019 1.000^** 0.667 -0.950 -0.979 0.225 SW 0.984 0.979 -0.248 1.000^* -0.229 0.205 0.659 -0.881 -0.988 LW 0.255 0.931 0.460 -0.987 0.989 -0.006 0.707 -0.498 -0.967 RW 0.966 0.998^* 0.237 -0.985 0.993 -0.418 0.228 -0.962 -0.944 TW 0.985 0.958 0.200 0.345 0.999^* -0.175 0.659 -0.655 -0.969

DM

TL -0.610 0.500 -0.655 n/a -0.619 0.986 0.930 n/a -0.091 LA -0.893 -0.962 -0.999^* -0.266 0.456 0.594 0.039 -0.412 0.366 TR -0.989 -1.000^** -0.982 -0.317 -0.412 0.997^* -0.622 -0.942 -0.655 SW -0.987 -0.996 -0.189 -0.948 -0.786 0.825 0.934 -0.999^* -0.456 LW -0.272 -0.966 -0.795 0.893 -0.287 0.686 0.909 -0.877 -0.364 RW -0.961 -0.985 -0.629 0.991 -0.524 0.325 0.992 -0.963 -0.289 TW -0.988 -0.984 -0.599 -0.610 -0.376 0.554 0.934 -0.953 -0.371

TL

LA 0.901 -0.243 0.628 n/a 0.417 0.453 0.403 n/a 0.894 TR 0.721 -0.500 0.500 n/a 0.971 0.971 -0.866 n/a -0.693 SW 0.731 -0.419 0.866 n/a 0.000 0.721 1.000^** n/a 0.928 LW 0.929 -0.261 0.979 n/a 0.930 0.558 0.998^* n/a 0.961 RW 0.367 -0.640 0.999^* n/a 0.993 0.165 0.877 n/a 0.980 TW 0.724 -0.339 0.997^* n/a 0.961 0.410 1.000^** n/a 0.959

LA

TR 0.950 0.962 0.988 0.999^* 0.623 0.654 -0.807 0.082 -0.943 SW 0.955 0.983 0.155 -0.053 -.909 0.945 0.394 0.362 0.662 LW 0.676 1.000* 0.773 0.195 0.722 0.993 0.453 0.799 0.734 RW 0.734 0.901 0.601 -0.137 0.519 0.954 -0.085 0.152 0.785 TW 0.951 0.995 0.570 0.926 0.653 0.999^* 1.000^** 0.669 0.729

TR

SW 1.000^** 0.996 0.000 0.000 -0.240 0.866 -0.861 0.959 -0.375 LW 0.412 0.966 0.666 0.143 0.991 0.741 -0.892 0.665 -0.466 RW 0.910 0.985 0.470 -0.189 0.992 0.397 -0.520 0.997^* -0.534 TW 1.000^** 0.984 0.437 0.945 0.999^* 0.617 -0.860 0.796 -0.459

SW

LW 0.426 0.986 0.746 -0.990 -0.367 0.977 0.998^* 0.849 0.995 RW 0.903 0.966 0.882 -0.982 -0.115 0.803 0.882 0.977 0.984 TW 1.000^** 0.996 0.900 0.327 -0.277 0.928 1.000^** 0.935 0.996 LW RW -0.004 0.908 0.972 0.945 0.966 0.911 0.850 0.716 0.997 TW 0.416 0.997 0.962 -0.189 0.995 0-.006 0.998^* 0.981 1.000^**

RW TW 0.908 0.940 0.999^* -0.500 0.986 0.967 0.883 0.837 0.996 Note: HT=Height; DM=Diameter; TL=Total leaves; LA=Leaf area; TR=Total roots; SW=Stem dry weight; LW=Leaf dry weight; RW=Root dry weight; TW=Whole seedling dry weight; Means in the same column followed by the same letter are not significantly different (p<0.05)*) or very significantly different (p<0.01) **), n/a =not available

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dium types. Furthermore, a study conducted by Shangjie et al. (2011) on a hydroponic of lettuce and Pak Choy showed that the vegetable types varied on optimal solution concentration, and different vegetable cultivars exhibited specific growth characteristics.

The result of the study as explained above, found that the inorganic nutrient in the hydroponic solution could be decreased by using biofertilizer. However, further study needs to be done to obtain organic substances from inexpensive, and easily available materials for hydroponic seedling production towards the organic product since the hydroponic culture of vegetable crops is commonly applied by the urban community which has no space for conventional farming. By using the organic nutrient in the hydroponic solution is expected to be produced more healthy vegetable.

CONCLUSIONS

From this study, we concluded that the nutrient solution containing 25% Beyonic StarT- mik@Lob and 75% commercial hydroponic solution (K4) was the appropriate nutrient solution for hydroponic seedling production of Pak Choy.

The organic seedling production plays an important role because it is the initial step in the practice of biological farming. Therefore, further study needs to be done to obtain organic substances for hydroponic seedling production towards the organic product.

ACKNOWLEDGEMENT

This work was funded by DIPA Biovillage 2016 of Research Center for Biotechnology-LIPI entitled Use of Germplasm Garden Compost for Or- ganic Vegetable Production. Authors would like to thanks, Dr. Enung Sri Mulyaningsih, Head of Plant Germplasm Garden of RC for Biotechno- logy for the use of the research facility. Thanks also to the technicians of the project, Heru Wibo- wo, A.Md., Yudi Slamet Hidayat, SP. and Roni Ramdani, SP. for their help in the experiments.

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